NAUUP – AQUAICBAS
Aquatic Activities UPArchive for March, 2008
Dolphin Bling Gets Girls/Botos (Golfinhos) Formas de Captivar as Fêmeas
By Charles Q. Choi, Special to LiveScience
Just as men can use fast cars or showy clothes to impress the ladies, so too do male Amazon river dolphins show off stuff to woo the opposite sex.
Among these dolphins, the attention-getter is a male carrying a branch or similar flotsam in its mouth. Such “player” behavior is a first to be documented in aquatic mammals and, among land mammals, it has previously been seen only in chimpanzees and humans, researchers said.
These new findings help show that humans are “not as different from other animals as some might like to think,” said researcher Anthony Martin, a behavioral ecologist and population biologist at the University of St. Andrews in Scotland.
Amazon river dolphins, also known as botos or pink river dolphins (Inia geoffrensis), live mostly off fish in the Amazon River basin, with the occasional turtle or crab.
The botos had often seemed to play with items such as sticks or lumps of hard clay, thrashing them against the surface of the water or tossing them with flicks of their heads.
One day scientists noticed that three botos that held objects in their mouths were all adult males. This prompted speculation that such behavior might not be play at all.
Martin and his colleagues carried out hundreds of subsequent observations of dolphins. Trying to live and work in the flooded Amazon forest was challenging, with investigators having to overcome things “like the heat and humidity, which destroys electronic equipment; opacity of the water, which is like milk coffee, you can’t see underwater; and the insects and fungi that busily turn our floating lab home into mush,” he said.
Martin and his colleagues found the overwhelming majority of those who carried items were adult males, which are larger and pinker than females.
“It’s particularly interesting that the complexity of this behavior in these dolphins is considerably greater than that in chimps,” Martin said. “Chimp males break off branches, thrash them around and make a lot of noise to show off how macho they are — bit like blokes with big motorbikes and Ferraris, I guess. Botos, however, are much more subtle, and often use their objects in what appears to be a ritualistic way.”
Males typically held objects when there were adult females present.
“This species has a mythical reputation for enchanting and seducing women in Amazon communities, and you could believe that they really are enchanting their own females with this object-carrying behavior,” Martin said.
Aggression among males — such as biting or striking another dolphin with the head or tail — was strongly linked with object-carrying, and perhaps was linked to access to females, the scientists added.
Although the scientists think they saw some females carry objects, “it’s possible some of these ‘females’ were actually pre-adult males, because some such males are the same size and color as some adult females,” Martin said. Even if these were females, “the number of examples of females carrying objects was tiny, and in any animal population you can expect to find some individuals who do things different.”
Martin noted this behavior was found in populations of botos that have probably been geographically isolated from each other for millions of years.
“It is therefore either ancestral to them all and therefore millions of years old or has evolved independently in each case,” Martin said. “Either way it does appear to be deep-rooted in their behavior and passed from one generation to the next. Some would argue that this is culture.”
Martin noted that “river dolphins are the most endangered and least understood of all cetaceans, and we are in a race to find out how to conserve them before they all disappear.”
Martin and his colleagues Vera da Silva and Peter Rothery detailed their findings online March 26 in the journal Biology Letters.
source:www.livescience.com
Low Oxygen and Molybdenum Levels in Ancient Oceans Delayed Evolution of Life by Two Billion Years/ Teoria sobre as Razões de um atraso Evolutivo: 2BA
UC Riverside., Calif. – A deficiency of oxygen and the heavy metal molybdenum in the ancient deep ocean may have delayed the evolution of animal life on Earth by nearly two billion years, a study led by UC Riverside biogeochemists has found.
The researchers arrived at their result by tracking molybdenum in black shales, which are a kind of sedimentary rock rich in organic matter and usually found in the deep ocean. Molybdenum is a key micronutrient for life and serves as a proxy for oceanic and atmospheric oxygen amounts.
Study results appear in the March 27 issue of Nature.
Following the initial rise of oxygen in the Earth’s atmosphere 2.4 billion years ago, oxygen was transferred to the surface ocean to support oxygen-demanding microorganims. Yet the diversity of these single-celled life forms remained low, and their multicellular descendants, the animals, did not appear until about 600 million years ago, explained Timothy Lyons, a professor of biogeochemistry in the Department of Earth Sciences and one of the study’s authors.
Suspecting that deficiencies in oxygen and molybdenum might explain this evolutionary lag, Lyons and his colleagues measured abundances of molybdenum in ancient marine sediments over time to estimate how much of the metal had been dissolved in the seawater in which the sediments formed.
The researchers found significant, firsthand evidence for a molybdenum-depleted ocean relative to the high levels measured in modern, oxygen-rich seawater.
“These molybdenum depletions may have retarded the development of complex life such as animals for almost two billion years of Earth history,” Lyons said. “The amount of molybdenum in the ocean probably played a major role in the development of early life. As in the case of iron today, molybdenum can be thought of as a life-affirming micronutrient that regulates the biological cycling of nitrogen in the ocean. [+]
Source: U Riverside
It hurts Dolphins to swim faster than 54kph near the surface/ Cavitação: Fenómeno físico que afecta os Golfinhos
img source: caltech.edu
It hurts Dolphins to swim faster than 54kph near the surface London, March 30 (ANI):
A pair of researchers from the Israel Institute of Technology in Haifa has discovered that it hurts dolphins to swim faster than about 54 kilometres per hour near the surface, but tuna do not suffer the same problem.
Gil Iosilevskii and Danny Weihs conducted a study to determining what limits the maximum speed at which fish like tuna and mackerel, and cetaceans like dolphins could swim.
The researchers carried out a series of calculations to model the tail and fins of these creatures for the purpose.
They found that, while muscle power limits the swimming speed of small fish, this is not the case for larger and more powerful swimmers like tuna and dolphins. “There are certain limits on swimming speed that are imposed irrespective of power,” New Scientist quoted Iosilevskii as saying.
The researcher said that one such limit is the frequency at which the swimmers can beat their tails to propel themselves forward, while the other is the formation of microscopic bubbles around the tail, a phenomenon known as “cavitation”.
The researcher duo reckons that cavitation can be the most important limiting factor for animals like dolphins, which have nerve ending in their tails. The bubbles form as a result of the pressure difference created by the movement of the fins, and this process produces the ribbons of tiny bubbles that stream behind a ship’s propeller.
When the bubbles collapse, they produce a shockwave that eats away the metal in propellers, something that is painful for dolphins. The researchers say that as per their calculations, within the top few metres of the water column, this happens when the dolphins reach 10 to 15 metres per second, or 36 to 54 kilometres per hour. Tuna, on the other hand, have “bony” tails without nerve endings, which is why they may sometimes break the speed limit imposed by the pain barrier. However, still, cavitation does slow tuna down when the bubbles collapse, they break the flow of water over the fish’s fins and tail, causing it to stall. The study has been reported in the Journal of the Royal. (ANI)
Sea cucumber inspires new plastic/Pepinos-do-Mar, base para novos Plásticos
Mason Inman
The skin of sea cucumbers was the inspiration for a new material that can change dramatically from rigid to floppy when soaked in water.
The material could be useful for brain implants that cause less inflammation, researchers say. A version switched by electric pulses that is currently in development could find many more uses – such as clothing that morphs into armour.
Sea cucumbers’ skin is usually supple, allowing them to slide through narrow spaces between rocks and corals. But when touched a defensive reaction makes their skin go rigid in seconds, thanks to enzymes that binds protein fibres together. A second set of enzymes can break those bonds to make the skin soft again.
Sea cucumber skin can become more than 10 times stiffer in this way, but the new material can go further – softening by more than 2500 times. Simply soaking the transparent material in warm water for 15 minutes is all it takes to complete the transformation. After drying out it is identical to its original rigid state.
The new material behaves differently to more common materials that go floppy in water like foam or cardboard. It changes its properties more dramatically and does not take on large amounts of water when soaked.
Cellulose ‘whiskers’
Developed by Stuart Rowan and Chris Weder of Case Western Reserve University, Cleveland, Ohio, US, the material is a polymer made from two different compounds and shot through with microscopic cellulose fibres. “It’s directly inspired by the sea cucumber,” Rowan says.
“We have the elastic polymer, so that’s the mimic for the sea cucumber skin, and then we put in the cellulose whiskers,” Rowan says. “You can get these from paper pulp, but we got ours from another little sea creature called a tunicate.”
When dry, the cellulose fibres keep the material rigid by forming a scaffold held together by hydrogen bonds. But water molecules are better at forming such bonds, so when wet, the fibres lose their grip on one another and bond to the water molecules instead.
The material could be useful for electrodes implanted into the brain, such as for patients with Parkinson’s disease or for brain control interfaces, the researchers say.
Electric switch
The rigid material could easily be inserted into brain tissue, before softening into its floppy state. That would reduce the problems with inflammation solid electrodes can cause.
Rowan says they’re now working on versions of the material that switch stiffness in response to a pulse of electricity.
“I think it is one of the most exciting recent opportunities in the design of new materials,” says Craig Hawker of the University of California in Santa Barbara, US. “It will open the door to applications in a number of different fields.”
“One can imagine protective clothing for example, which is flexible and comfortable to wear, but becomes rigid and protective when necessary,” Hawker adds. “This is essentially what sea cucumbers use this process for.” Robert Langer of Massachusetts Institute of Technology, US, adds, “perhaps it could also be used as a stimuli responsive system for drug delivery”.
Journal reference: Science (DOI: 10.1126/science.1153307)
Source: scubatravel.co.uk
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Pepinos-do-Mar (AKA Holotúrias) e mais sobre Equinodermes:>
Manual Educacional sobre Golfinhos (CMS) – traduzido pela CETUS/ CMS Dolphin Manual multilanguage download
(Eng version below)
Este manual existe agora em nove línguas!
Pretende-se com esta iniciativa divulgar factos e curiosidades sobre estas criaturas fascinantes junto dos mais novos assim como alertar os mesmos para os perigos que os golfinhos encontram e como todos nós podemos fazer algo para os proteger.
A ideia é distribuir a versão electrónica deste manual, grátis, por escolas, câmaras municipais ou clubes que possam imprimir e utilizar o manual em actividades educacionais, em Portugal e países lusófonos. A Cetus está também a tentar arranjar financiamento para imprimir o manual e distribuir por escolas e clubes que não tenham possibilidades financeiras para a sua impressão.
Para obter uma versão de alta qualidade do manual para impressão e distribuição por escolas,
ou para patrocinar a impressão e distribuição do manual por favor contacte:
Sónia Mendes:
s.mendes[at] abdn.ac.uk
_______version:
CETUS has translated the CMS Dolphin Manual to the Portuguese language:
This Manual was designed for raising awareness of dolphins in the wild, the threats they face to their survival and actions that could help with their conservation and the protection of their habitats and ecosystems.
High resolution prints can be obtained upon request, as well as funding cooperation so this manual can be distributed on schools, city halls or clubs without financial ability to cope with the massive printing process.
Sónia Mendes:
s.mendes[at] abdn.ac.uk
Here you can view the official Dolphin Manual
of the “Year of the Dolphin” in:
English
German
French
Spanish
Italian
Arabic
Greek
Turkish
Portuguese
Quadrapalegic and Former Indy Racer to be Introduced to Scuba Diving/Ex-Piloto de Indy Racing, Tetraplégico, inicia-se no Mergulho
Schmidt will make his first scuba dive and ‘Swim with the Fishes’ on Thursday, April 3 at 3:30 p.m. at the Coral Reef Exhibit at The Florida Aquarium. This scuba diving exhibition is part of Schmidt’s continuing demonstrations on the limitless possibilities available to individuals with spinal cord injuries…
Though Sam Schmidt was paralyzed from the chest down in a racing accident, he considers himself one of the lucky individuals who, through strong personal faith and desire continues to enjoy all aspects of life. Participating in Swim with the Fishes at The Florida Aquarium will be challenging, rewarding and inspirational to other individuals with spinal cord injuries. To learn about his efforts visit:
This article comes from DiveNews.Com
Este senhor lançou-se num novo desafio: das corridas para o mergulho, apesar de tetraplégico.
No nosso País existem instructores de Mergulho qualificados para acompanhar pessoas com esta vontade de viver e de conhecer novos horizontes.
Que fique aqui um bom exemplo, para todos!
exposição de fotografia "Cetáceos da Costa Portuguesa": Faculdade Ciências do Porto
[Divulgação] Serão da Escosub 4 Abril: Temas: "Legislação de Mergulho; Seguros; Viagens"
seguros de mergulho”.
Vamos iniciar também a preparação das nossas
viagens de Verão Açores e Sharm.
Exposição: Ilustração Científica de Pedro Salgado/Scientific Illustration Exhibition by Pedro Salgado
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Aconselhada vivamente a visita;
Há alguns anos alguns alunos de CMA tiveram a oportunidade de fazer o curso com este Sr. da Ilustração Científica.
Vale mesmo a pena!
Pormenores que nem a fotografia consegue captar, ficam minuciosamente patentes na ilustração.
End Commercial Harvest of Freshwater Turtles/Parar com o comércio de Tartarugas de Água Doce
From: Center for Biological Diversity
Conservation, Health Groups Petition Four Southern States to End Commercial Harvest of Freshwater Turtles
TUCSON, AZ—) TUCSON, Ariz.— Conservation and health groups are seeking to end unsustainable commercial harvest of freshwater turtles in four southern states and to stop the export of contaminated turtles to international food markets. The Center for Biological Diversity today filed emergency petitions with the states of Florida, Georgia, Oklahoma, and Texas to ban commercial turtle harvesting in public and private waters, to prevent further population declines of native southern turtle populations, and to protect public health. Turtles collected in these states and sold as food are often contaminated with mercury, PCBs, and pesticides.
Wildlife exporters and dealers are commercially harvesting massive and unsustainable numbers of wild freshwater turtles from Oklahoma, Florida, and Georgia, the few southern states that continue to allow unlimited and unregulated take of turtles. Herpetologists have reported drastic reductions in numbers and even the disappearance of many southern map turtle species in Georgia and Florida, especially in the panhandle. Recent surveys by Oklahoma State University show depletions and extinction of freshwater turtles in many Oklahoma streams, and commercial turtle buyers in Oklahoma reported purchasing almost 750,000 wild-caught turtles from 1994 to 1999. Over a quarter million wild-caught adult turtles captured in Texas were exported from Dallas Fort Worth Airport to Asia for human consumption from 2002 to 2005.
“Unregulated commercial trappers are capturing appalling numbers of freshwater turtles in southern states, including rare map turtle species that are so depleted they may need protection under the Endangered Species Act,“ said Jeff Miller, conservation advocate with the Center for Biological Diversity. ”Collectors could legally harvest every non-protected turtle that exists in the wild under the inadequate regulations that currently exist in Florida, Georgia and Oklahoma. These turtles are an important part of aquatic ecosystems and should not be allowed to be wiped out.” [+]
source: ENN News
